Influence of grain size on radionuclide activity concentrations and radiological hazard of building material samples

The knowledge of radioactivity content in various radionuclides in building materials plays an important role in health physics; therefore, we measured the amount of naturally occurring radionuclides in building material (sand, granite, marble, and limestone) samples of different grain sizes by using NaI (Tl) and MCA1024 gamma-ray spectrometers. Data analyses were performed to determine 226Ra, 232Th, and 4°K activity concentrations. The results revealed an inverse relationship between activity concentration and grain size of the samples. The radium equivalent activity (Raeq), representative level index I, and annual absorbed dose rate were calculated. •Measurement of naturally occurring radionuclides in different grain sizes for some building material samples.•We determined radium equivalent activity, the representative level index, and annual absorbed dose rate for all samples.•The radionuclide activity concentrations and radiological hazard depends on the grain size.